Chain lock alarm



Oct. 15, 1968 P. M. HAWKINS 3,406,386

CHAIN LOCK ALARM Filed Oct. 4, 1965 5 Sheets-Sheet 1 INVENTOR.

PAuL "Aw/soy Min-1km BY Oct. 15, 1968 P. M. HAWKINS 3,406,386

CHAIN LOCK ALARM Filed Oct. 4, 1965 3 Sheets-Sheet 2 I :L .4. 51 40 HArrp Oct. 15, 1968 P. M. HAWKINS CHAIN LOCK ALARM 3 Sheets-Sheet 5 FiledOct. 4, 1965 I i E L ITII IIIIIJ. I 4 Huh T L gti hmwwt i I m nH Hl l lHl nu lxwnm WHI I I I will E M$ INVENTOR. q PAUL 400mm HAWK/IVS N BY IUnited States Patent 3,406,386 CHAIN LOCK ALARM Paul Maddison Hawkins,Jericho, N.Y., assignor to General Alarm Corporation, New York, N.Y., acorporation of Delaware Filed Oct. 4, 1965, Ser. No. 492,455 7 13Claims. (Cl. 340-274) ABSTRACT OF THE DISCLOSURE A chain lock-alarmarrangement wherein a flexible chain element utilized for limiting theamount by which a closure may be opened, is arranged in conjunction withan alarm in such a manner that excessive force produced upon the chainwill cause the alarm to be actuated.

This invention relates to a combined lock and alarm, and moreparticularly, to a lock of the type wherein a chain allows a door, forexample, to swing open a limited distance relatively to its jamb, andmeans for sounding an alarm in the event that a given force is appliedto the door while ajar to tension the chain, or in certain aspects ofthe invention, while the door is fully closed.

Heretofore, a number of lock alarm-s have been proposed wherein anexcessive tension on the chain has been etfective to sound a bellthrough a mechanical linkage or clock work mechanism. However, thoselock alarms with which I am familiar have not been commerciallysuccessful, possibly because of the ease with which a prospectiveintruder could reach in through the partially open door and muflle or,in some cases, actually unscrew or otherwise destroy the bell which wasalways mounted on the jamb within reach of anyone at the door. Then, toomany such alarms were constructed to sound only while the prescribedtension was applied so that when the intruder heard the alarm, the soundcould be stopped simply by relaxing the pressure on the door, possiblybefore anyone was aware of the intended intrusion.

I have actually constructed a successfully operating and commerciallydes'nable chain lock alarm that overcomes the foregoing difficulties anddisadvantages. Thus, my invention contemplates a chain lock incombination with an alarm for use in connection with relatively moveablemembers such as a door and jamb, window and sash etc., comprising aflexible chain, means on one of said members for detachably mounting anend of the chain, and a normally open switch mounted on the othermember, switch operating means moveable to actuate said switch to closedposition, an alarm, electrical means such as a power source andappropriate circuitry are provided to operate the alarm when the switchis closed, and the chain is connected at its other end to the switchoperating means whereby the chain shifts the operating means to switchclosing position upon the application of a predetermined force to one ofthe members to move it relatively to the other. The term chain isintended to include any flexible elongate member suitable for theintended purpose. My invention also contemplates, in one aspect thereof,the inclusion of a dead bolt arranged to actuate the alarm when apredetermined force is exerted upon the door when it is fully closed andlocked.

As a feature of my invention, the alarm may be positioned near the door,or at any suitable remote location, and it may, of course, be of thevisual or audible type, or both. I also prefer to provide a housingaround the alarm mechanism, particularly in those installations whereinthe alarm is mounted adjacent a door, for example, to preventinterference or tampering by prospective intruders.

The switch operating means may be a lever mounted for pivotal movementagainst the force of an adjustable spring and formed with means forshifting the switch to closed position when such pivotal movementoccurs. The chain is connected to the lever and induces movement of samewhen under suflicient tension, and the spring is adjustable so as tovary the force required to actuate the alarm to suit the needs of eachparticular installation. In one embodiment of the invention I utilizethe housing to perform the function of the aforementioned lever bycausing it to tilt against the force of a spring upon application of apredetermined force to the door. The housing may also be utilized toactuate the alarm switch when an attempt is made to force or jimmy thedoor when same is dead locked.

It is also a feature of this invention that the lever or housingactuates the switch, but upon relaxation of the actuating force, thealarm continues even though the lever or housing returns to its originalposition under the influence of the spring. This is accomplished withoutthe need of costly relays by forming the lever or housing with anopening so dimensioned as to engage a switch tab and close the switchduring movement in one direction, but may shift back to its originalposition without engaging the tab. The alarm, once actuated, will thusremain in actuated condition until manually shut off.

Another important feature of my invention resides in the provision of apanic alarm and/or testing facility, whereby the operative condition ofthe alarm and its circuit components may be tested at will or an alarmsounded. To this end, I provide a button mounted conveniently for manualdepression to bypass the actuating switch and complete the alarmenergizing circuit, thus advising of the condition of the power source,alarm mechanism and circuitry components or sounding an alarm. However,in certain embodiments of the invention, the alarm actuating switch maybe manually accessible for test purposes, in which case a separate testbutton and bypass circuit is unnecessary.

There has thus been outlined rather broadly the more important featuresof the invention in order that the de tailed description thereof thatfollows may be better understood, and in order that the presentcontribution to the art may be better appreciated. There are, of course,additional features of the invention that will be described hereinafterand which will form the subject of the claims appended hereto. Thoseskilled in the art will appreciate that the conception upon which thisdisclosure is based may readily be utilized asa basis for the designingof other structures for carrying out the several purposes of theinvention. It is important, therefore, that the claims be regarded asincluding such equivalent construction as do not depart from the spiritand scope of the invention.

A specific embodiment of the invention has been chosen for purposes ofillustration and description, and is shown in the accompanying drawings,forming a part of the specification wherein:

FIG. 1 is a view of the present lock and alarm combination as it may beused in connection with a door and jamb;

FIG. 2 is a front view of the alarm with the housing cover removed;

FIG. 3A is a side view of part of the switch operating mechanism in theolf position;

FIG. 3B is a view similar to FIG. 3A but showing the parts in the onposition;

FIG. 4 is a side elevational view of another embodiment of my inventionwith some of the internal parts illustrated in broken lines, and shownin inactive position;

FIG. 5 is similar to FIG. 4, but shows the apparatus in active position;

FIG. 6 is a plan view of the apparatus of FIGS. 4 and 5 without thechain;

FIGS. 7 and 8 are views similar to FIGS. 4 and 5 but illustrating thechain alarm system in combination with a dead bolt; and

FIG. 9 is a top view of the device of FIGS. 7 and 8 with the housingremoved.

Referring now to the drawings, and more particularly to FIG. 1 thereof,there is shown a door 10 and jamb 11 in connection with which apreferred form of my invention may be put to use. Thus, I mount on thedoor a plate 12 formed with an elongate T-shaped slot 14 shaped toreceive at the juncture of its horizontal and vertical arms a groovedbolt or chain anchor 15 which may be positioned at the bottom of thevertical arm of the slot to keep taut the chain 13 to which it isattached, and thus keep the door closed; or the bolt may be positionedin the horizontal arm to permit the door to swing ajar a slight distancefor identification of a caller while maintaining security. The T-shapeof the slot 14 allows the same plate 12 to be mounted on the jamb ifdesired or on left or right handed doors.

In accordance with the present illustration, I mount on the jambopposite the plate 12 a housing 16 comprising a back plate 17 and acover 19 held to the back plate by a screw 20. Within the housing, Iprovide an alarm 21 such as a conventional buzzer, bell or the like, anda battery 22 supported in clip 24. The power circuit includes a singlepole, single throw switch 25 with an operating handle 26 extendinglaterally thereof. Suitable wiring is provided to enable the batterysource to energize the alarm when the switch is closed.

At this point it should be understood that while I have shown the alarmas a buzzer located in the housing, it can take the form of a flashinglight, for example, and may be located remote from the lock, as forinstance at a central guards office in the building, or at bothlocations. Where a remote alarm is employed, a miniature transmitter maybe used in lieu of the wiring shown to signal the remote alarm.

In order to actuate the alarm I provide switch operating means in theform of a lever 28 mounted in the housing 16 to pivot about pin 27. Thelever has a projection 29 formed with a hole 30 through which a screw 31extends, the latter being threaded into a portion of the housing. Acompression spring 32 surrounds the screw and bears at one end againstthe projection 29 and at the other against the screw head so thatclockwise pivotal movement of the lever, as viewed, is resisted by thespring. The spring tension may be adjusted to the desired value byadjusting the screw 31.

The lever 28 is also formed with a square opening or hole 34, the sidesof which embrace the switch handle 26; but when the parts are in theirnormal off position, the hole 34 and handle 26 are so related that thehandle extends into the hole adjacent the left side thereof, as viewedin FIG. 3A. The hole is actually of larger dimension than is necessaryto embrace the handle 26, for a reason to be later described.

The side of the housing cover has an arcuate opening or hole 35 locatedbetween the pivot pin 27 and the hole 34- in lever 28. A rivet or bolt36 which is permanently affixed to the lever, extends through theopening 35 and an end of the chain 13 is attached to it.

In operation, when the door is closed, the chain anchor 15 may bepositioned in the vertical or horizontal arm of slot 14. If in thevertical arm of the slot, any attempt to open the door will place thechain 13 under tension; if in the horizontal arm of the slot, the doormay be opened somewhat before the chain comes under tension. In anycase, if a chain tensioning force is applied to the door to create amovement in the lever 28 sufficient to draw the latter from its offposition (FIG. 3A) to the position shown in FIG. 3B, it will shift theswitch handle 26 to the on position, thus actuating the alarm. Becausethe opening 34 is oversized and eccentric relatively to the handle 26,the switch will remain in the on position even if the chain tension issubsequently relaxed so. that the lever 28 returns to its originalposition.

In installations wherein the alarm is mounted adjacent the door, thehousing prevents a would-be intruder from interfering with operation ofthe alarm.

To increase the security of the system, the screw 20 may be formed witha special head as shown in FIG. 1 so that ordinary screw drivers willnot be effective for removal of the cover 19. The tenant will, ofcourse, be provided with a special key or screw driver for removing thecover to service the system.

The cover 19 may also have a circular opneing 39 (FIG. 1) for mountingthe chain anchor 15 when the door is'opened wide.

To test the alarm system or sound a panic alarm, I provide a push button37 which projects out of the bot tom of the housing 16. When depressed,the button simply grounds the negative side of the battery 22 to thehousing to complete the circuit to the alarm which is also grounded tothe housing. The button 37 thus effectively bypasses the switch 25.

Turning now to FIG. 4, I show a further embodiment of the inventionaccording to which the chain 13 is secured to a decorative anchor 40mounted on the door panel or jamb 11, while the housing 41 is mounted ona base plate 42 secured to the door 10. It is to be noted here that theedge of the housing 41 adjacent the plate 42 is relieved slightly at theright hand side, as viewed, so that the relieved portion 44 of edge isnormally slightly angulatcd relatively to the surface of the plate. Thehousing is secured to the plate 42 by a screw 47 that extends downthrough a cylindrical recess 49 formed in the housing, and into theplate 42. A spring 50 bears against the bottom of the recess. andagainst the head of the screw to bias the housing into the positionshown in FIG. 4.

As has been stated, one end of the chain 13 is secured to the anchor 40.The other end of the chain is connected to a chain anchor 45 adapted toenter a chain anchor slot 46 (FIG. 6) at its large end and slidelengthwise in its slot to allow for partial opening of the door whileretaining chain security. A similar hole 48 has a shortened slot and mayaccept the chain anchor 45 without allowing for partial opening of thedoor.

The housing 41 has a slot 51 formed in one of its sides through whichslot a switch handle 52 (similar to handle 26 of FIGS. 2, 3A and 3B)extends, and an alarm 53 and one or more batteries 22 may be containedwithin the housing. It will be understood that, as in the previouslydescribed embodiment, the power source and alarm may be remotelylocated. A simple series circuit (not shown) is arranged to supply powerfrom the batteries to the alarm when the switch 54 is closed.

In the operation of the embodiment of FIGS. 4,5 and 6 of my invention,the chain is set as shown in FIG. 4 and is, of course, of sufficientlength so that the door may be opened somewhat without actuating thealarm. How ever, if the door is opened and then forced beyond apredetermined limit, the chain serves to rock the housing 41 about thepoint of juncture of the plane of the relieved portion 44 with the planeof remainder of the inner edge of the housing. Thus, this point ofjuncture becomes a fulcrum about which the housing rocks to the positionshown in FIG. 5. The spring 50 resists this movement and may be adjustedby means of the screw 47, to increase or decrease the load necessary tobe overcome in order to rock the housing. The housing moves to theposition of FIG. 5, the lower edge of the slot 51 (as viewed in FIGS. 4and 5) raises the switch handle 52 from the inactive position of FIG. 4to the switch closing position of FIG. 5. Upon relaxation of the openingforce, the spring 50 returns the housing 41 to its normal position (FIG.4) but, because the slot 51 is longer than the switch handle 52, the armremains in switch closed position and the alarm 53 continues to functionuntil the switch is thrown manually to off position. Of course,

a holding relay could be used to maintain the alarm circuit closed, butI find the described system simple and inexpensive. The switch may bethrown to closed position at any time to test the circuit and powersupply or sound a panic alarm. If the chain anchor 45 is positioned inhold 48, the same switch actuation will occur upon application of forceagainst the door when in fully closed position.

If desired for esthetic purposes, the chain may be encased in a sleeveof leather or plastic, for example, and the housing may be formed sothat the chain anchor slot 46 is at the bottom of a groove of a depthwhereby the chain will be flush with the surface of the housing.

A further embodiment of my invention is shown in FIGS. 7 to 9 whereinthe chain lock and alarm are substantially identical to those alreadydescribed in connection with FIGS. 4 to 6. However, the housing 60 andstrike plate 61 are larger than those described so that the former'canhouse, in addition to the alarm unit, batteries and switch, a dead boltlock mechanism identified generally by the numeral 62 in FIG. 9, and thelatter becomes a keeper for a dead bolt. This lock mechanism 62 isconventional and comprises briefly, a rotatable crank 64 pivoted to aconnecting arm 65 that is in turn pivotally connected at 66 to a deadbolt 67. The crank 64 can swing only 180 between bolt retracting andprojecting positions, its limits of movement being defined by stops 69.A torsion spring 70 having one end anchored to the arm 65 and the otherto a relatively stationary member, provides a toggle action to movementsof the bolt. The crank is manually actuated from inside the door by athumb turn 71 (FIGS. 7 and 8) and from outside the door by a keyoperated lock cylinder 72.

It will be appreciated that by combining a dead bolt with the apparatusof FIGS. 4 to 6, I contribute an additional measure of protection inthat any effort to force or jimmy the door when the bolt is thrown willcause the bolt, to bear against the inner surface of the keeper and thustilt the housing 74 about the fulcrum point 75 bearing against the baseplate 76, thus lifting the far end of the housing and with it the switchactuating handle 77 to the position shown in FIG. 8 wherefrom it closesalarm switch 79 to place the alarm 80 in circuit with the power sourcesuch as batteries 78. The alarm may be of several types, as mentioned,and in any location. The slot 81 in the housing through which the switchhandle 77 projects, is again dimensioned to permit the switch to remainin switch closed position even when the force on the door is relaxed andthe adjustable spring 84 returns the housing to its normal position.

1 The chain lock operates to actuate the alarm in the r manner alreadydescribed in connection with FIGS. 4 to 6. t

In this embodiment of the invention I have arranged for the provision,where desired, of a bolt condition indicator which may constitute asimple flag moveable with the thumb turn or lock cylinder to indicatebolt condition. However, I prefer to utilize an electric lamp which islighted when the bolt 67 is retracted. Accordingly, I provide a lamp 86beneath a viewing opening in the keeper 61 and within the keeper Ilocate a switch 87 such as a microswitch operable when the bolt isthrown to protracted position to open a series circuit which includes abattery 89, thus to deenergize the lamp. Upon retraction of the bolt,the switch closes to energize the lamp, thus indicating the retractedcondition of the bolt. For this urpose, house power may be used ifdesired in lieu of the battery 89. A viewing opening may be located onthe opposite side of the lamp 86 so that the bolt condition will beobservable from the exterior of the door.

It will be appreciated of course that the housing and keeper may bemortised into the door and jamb rather than surface mounted.

A further feature of my invention resides in the provision of a keylock-out device which operates to prevent 6 unlocking of the lock fromoutside whenever the chain anchor 91 (FIG. 7) is slid forward in itsslot 90 (FIG. 9) to engage the thumb-turn 71 (FIG. 8). The chain anchor91 is engaged in the anchor slot 90 and can be so positioned, as shownin its dotted outlined position, to engage a slot 92 (FIG. 8) in thethumb-turn 71 when the thumb-turn is turned to its locked position asshown in FIG. 7. This prevents retraction of the dead bolt by any meansuntil the chain anchor 91 is first removed from the slot 92 of thethumb-turn 71.

From the foregoing description, it will be seen that I have provided acombined lock and alarm which avoids several difficulties noted inconnection with prior efforts in the art, and which is tamper proof,permits remote positioning of the alarm and including means for testingthe circuitry at will or sounding a panic alarm. I also contribute meansfor actuating the alarm upon application of an excessive force to thechain when the door is opened, and even when the door is closed andlocked as by a dead bolt. Where a dead bolt is employed, a boltcondition in dicator may conveniently be included as part of my novelcontribution. Thus, I actually contribute a relatively simple, butreliable and inexpensive, lock and alarm system. It will be appreciatedthat the present system is not confined only to use in connection withdoors, as in the illustrative embodiments, but may be used to guardwindows and other closures.

I believe that the construction and operation of my novel combined lockand alarm will now be understood, and that the advantages of myinvention will be fully appreciated by those persons skilled in the art.

I claim:

1. In apparatus of the class described, the combination of a chain lockand alarm for use in connection with relatively moveable memberscomprising, a flexible chain, means securing an end of said chain to oneof said members, a housing and normally open switch, means within saidhousing mounted on the other of said members, an alarm, means includinga power source in circuit with said alarm and switch and operating saidalarm when said switch is closed, said housing being fulcrumed to rockrelatively to the member upon which it is mounted and having an openingthrough which said switch projects for actuation to closed position whensaid housing rocks about its fulcrum, spring means resisting saidrocking movement, and means securing the other end of said chain to saidhousing whereby said chain exerts a force upon said housing to rock sameand close said switch upon application of a predetermined force to saiddoor, one of said chain securing members being manually releasable.

2. Apparatus according to claim 1, wherein said hous ing has a keyholeslot and said chain has a grooved bolt at its end for sliding movementin said slot and said opening in said housing is so dimensionedrelatively to the projecting part of said switch as to permit same toremain in circuit closing position upon return of said housing to normalposition under the influence of said spring means when saidpredetermined force is released.

3. In apparatus of the class described, the combination of a lock andalarm for use in connection with relatively moveable members comprising,a flexible chain, mounting means on each of said members for anchoringan end of said chain, a normally open switch on one of said members, analarm, means including a power source in circuit with said alarm andswitch and operating said alarm when said switch is closed, one of saidmounting means housing said switch being contoured to rock relatively toits respective member upon the application of a predetermined force tosaid chain and engaging and shifting said switch to circuit closingposition upon such rocking movement, said chain being detachable fromone of said members, and a manually operable bolt and keeper mounted forcooperation on respective of said members to maintain same relativelyimmoveable and to shift said switch operating means to switch closingposition upon the application of a redetermined force upon said bolt.

4. In apparatus of the class described, the combination of a chain lockand alarm for use in connection with relatively move-able memberscomprising, a flexible chain, means securing an end of said chain to oneof said mem bers, a housing and normally open switch, means within saidhousing mounted on the other of said members,,an alarm, means includinga .power source in circuit with said alarm and switch and operating saidalarm when said switch is closed, said housing beingv fulcrurned to rockrelatively to the member upon which it is mounted and having an openingthrough which said switch projects for actuationto closed position whensaid housing rocks about its fulcrum, spring means resisting saidrocking movement, means securing the other end of said chain to saidhousing whereby saidch'ain exerts a force upon said housing to rock sameand close said-switch upon application of a predetermined force to saiddoor, one of said chain securing members being manually releasable, anda manually operable bolt and keeper mounted for cooperation onrespective of said members to maintain same relatively immove; able andto shift said switch operating means to switch closing position upon theapplication of a predetermined force upon said bolt.

5. Apparatus according to claim 4, wherein the position of said bolt isindicated by provision of an electric indicator and an indicator controlswitch operable by said bolt.

6. In apparatus of the class described, achain lock having a key lockout feature comprising a lock adapted to be mounted on one side of adoor with a thu mb-tur-n on said one side for manipulating said lock andmeans adapted to be engaged by a key from the opposite side of 'saiddoor also for manipulating said lock with consequent turning of saidthumb-turn, a flexible chain, means forattaching one end of said chainsecurely to a door casing, a chain anchor attached to the opposite endof said chain, guide means on said lock for securing said chain anchorto said lock and for allowing limited sliding movement of said chainanchor on said lock, and means associated with said chain anchor forengaging said thumb-turn and preventing its rotation when said chainanchor is moved to a given position on said lock.

7. A chain lock-alarm dCViCeCOmPIiSiHg in combination, a flexible chain,means for securing one end of said chain to one of two relativelymovable members, a housing, means for securing the other end of saidchain to said housing, means for mounting said housing to the other ofsaid members in a manner permitting limited movement of said housing onsaid other member inresponse to tension in said chain when said membersare forced toward a mutually separated condition, spring means arrangedto bias said housing against said limited movement of said housing, andan alarm actuating switch enclosed by said housing, said switchincluding a switch arm arranged such that movements of said housingcaused by excessive tension on said chain operates 'said switch to analarm actuating condition.

8. A chain lock-alarm device as in claim 7 wherein a bolt is proyided toproject from and to retract into said housing,. for locking andunlocking respectively said members in closed condition, wherebyforcing,of said members as so locked toward anopen condition will cause saidbolt to move said housing in a manner-to operatesaidswitch to an alarmactuating;co,ndition.;.. -I 9. A chain lock-alarm device comprising incombination, a flexible chain,.means for securingtone endof said chainto one of two relativelymov'able members, a housing arranged to besecured to the other of saidrnembers, an electrical -:alarm-,.actuatingswitch of the type which; remains in any condition to -whichit.is.set,.-said switch= being carried in said-housing'a switchactuating member .alsocarriedtin said housing and guided entirelybysa-id housing for movement between two fixed; posh tions therein;spring means with said housing hias ing said actuating arrnvto one ofsaid-twopositions, means for securing theot-hernendtof said-chainto-said arm for causingzs aidarm to. be pulled-by said chain tOriiSother positiomby-Jensionimposed; upon said-chain when .saidmembers;are=-torced-toward a. mutually separated condi: tionandmeansinterconnecting said switch and said arm in a mannemsuch: thatmovement-otsaid arm to its-said other position operates said switch.; toan;alarm-actuating condition, and movementofsaid switch actuating memberto its said-onepositiondoes not operatesaid .switch. 10.- Achain-lock-alarm de.vice. as zinxclai'm 9-wherein saidinterconnectingzrneans.comprises a switch arm extending from saidswitch-intoengagement;with said aetuating arm, .one :ofsaid armsihavinga portion whichsextends through an opening in theother ofsaid arms.=11-.-A chain lock-alarm device as in claim 10 wherein said openingiselongated .inthe direction-of actuating arm movement by an-qamount atleast-as great as the distance of movement necessary to operate said-:a1arm actuating-switch whereby return movement of said actuating armwill not cause alarmzdeactuating movement .of said switch arm. .1 1

-12. A chain lock-alarm device. as in claim 9..wherein there is providedan alarm within said housing-and arrangedto be actuated by operation'otsaid alarm actuating switch. 1 1 13.. A chain lock-alarm device as inclaim 9 wherein there is provided in said'housing a test switchconnected in parallel-with said alarm actuating switch.

References Cited UNITED STATES PATENTS JOHN w. CALDWELL,-PriniaryExaminer.

L. TRAFTON, .dssistdnt Exdrpiner.

